"I think that's what it was: the devil's work," she says. "When all that is going on, I was just thinking to myself: 'Well, the devil is not going to win. He's not going to win over my heart. He is not going to win.'"

She has to wait two more weeks to witness the death of Andrew Allen Cook.

Hendrickson declined to speak to us on camera, but did discuss her son, Grant Hendrickson, and his girlfriend, Michelle Cartagena.

The two Mercer University students were gunned down January 2, 1995. The investigation took about two years before Cook was arrested.

The wait and the wondering took a toll on Mary Hendrickson.

She says, "I suspected everyone I knew."

Police said Cook fired two guns 19 times at the couple on Lake Juliette. He was convicted in 1998 after his father, retired FBI agent John Cook, testified that his son confessed to murdering the couple.

The next day, Andrew Cook was sentenced to death. He's been on death row ever since.

Monroe County Sheriff John Cary Bittick spent hundreds of hours investigating the crime over the two years before Cook's arrest.

"In my entire career this probably has been the most tragic case that I've seen in middle Georgia," Bittick says.

He plans to join Mary Hendrickson on February 21 when Cook is sentenced to die by lethal injection.

"It's clearly a death penalty case," Bittick says. "I'm certainly a proponent for the death penalty."

Hendrickson says, "I'm planning on going up there. I'll be there. I don't know if I'll watch or not."

Authorities say there was no known connection between Cook and his victims.